mm: do check on shared pages only if a vma is inherited (v2)

v2: restore page contents directly into memory
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-restore.c

@@ -339,26 +339,31 @@ static int restore_priv_vma_content(pid_t pid)
 			}
 
 			off = (va - vma->vma.start) / PAGE_SIZE;
+			p = decode_pointer((off) * PAGE_SIZE +
+					vma_premmaped_start(&vma->vma));
 
 			set_bit(off, vma->page_bitmap);
-			if (vma->ppage_bitmap)
+			if (vma->ppage_bitmap) { /* inherited vma */
 				clear_bit(off, vma->ppage_bitmap);
 
 				ret = pr.read_page(&pr, va, buf);
 				if (ret < 0)
 					break;
-
 				va += PAGE_SIZE;
 
-			p = decode_pointer((off) * PAGE_SIZE +
-					vma_premmaped_start(&vma->vma));
-
 				if (memcmp(p, buf, PAGE_SIZE) == 0) {
-				nr_shared++;
+					nr_shared++; /* the page is cowed */
 					continue;
 				}
 
 				memcpy(p, buf, PAGE_SIZE);
+			} else {
+				ret = pr.read_page(&pr, va, p);
+				if (ret < 0)
+					break;
+				va += PAGE_SIZE;
+			}
+
 			nr_restored++;
 		}